Cleanup of (EE) api settings.md doc

What does this MR do?

Replaces ~"Community Contribution" https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/6600. Rebased and resolved conflicts.

CE MR https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/21474

Author's checklist

• Apply the correct labels and milestone
• Crosslink the document from the higher-level index
• Crosslink the document from other subject-related docs
• Correctly apply the product badges and tiers
• Port the MR to EE (or backport from CE): always recommended, required when the ee-compat-check job fails

Review checklist

• Your team's review (required)
• PM's review (recommended, but not a blocker)
• Technical writer's review (required)
• Merge the EE-MR first, CE-MR afterwards

	2 Warnings
⚠	This merge request does not have any assignee yet. Setting an assignee clarifies who needs to take action on the merge request at any given time.
⚠	This merge request does not refer to an existing milestone.

Generated by 🚫 Danger

changed milestone to %11.3

marked the checklist item Apply the correct labels and milestone as completed

marked the checklist item Crosslink the document from the higher-level index as completed

marked the checklist item Crosslink the document from other subject-related docs as completed

marked the checklist item Correctly apply the product badges and tiers as completed

marked the checklist item Port the MR to EE (or backport from CE): always recommended, required when the ee-compat-check job fails as completed

marked the checklist item Your team's review (required) as completed

marked the checklist item PM's review (recommended, but not a blocker) as completed

marked the checklist item Technical writer's review (required) as completed

changed the description

@rymai assigning to you since my team is out 😄

assigned to @rymai

@axil Thank you, looks good to me! ❤ 💛 💚 🚀

approved this merge request

marked the checklist item Merge the EE-MR first, CE-MR afterwards as completed

merged

mentioned in commit bb7ff51c

mentioned in merge request !6600 (closed)

@axil @rymai Yay, nice to see it finally merged! Thanks for the squash and rebase @axil, I was just waiting for the right time, but I guess that time was now 😉

added Enterprise Edition label

added typemaintenance label